Nano-Crystalline Sulfated-Zirconia for Friedel-Crafts Acetylation of Methyl Salicylate

In recent years, the use of solid acidic catalysts such as clays and zeolites has attracted significant attention in different areas of organic synthesis. [1] Among the solid acids reported, sulfated zirconia have been found to be highly active catalysts in many acid catalyzed reactions [2, 3]. Many large volume applications based on sulfated zirconia are reported in the literature, especially in the petroleum industry for alkylation, isomerization and cracking reactions. In particular, sulphated zirconia (SZ) has been shown to be active for a number of reactions. Interestingly, sulfated zirconia exhibits excellent activity for a wide range of organic synthesis and transformation reactions. Friedel-Crafts alkylation is an important class of reactions in organic chemistry. In general, such reactions are carried out using homogeneous acid catalysts such as AlCl3, FeCl3, and H2SO4 [4]. However, these catalysts suffer from problems such as corrosion, handling, toxicity, and separation and recovery of the catalyst. Therefore, many efforts have been made to replace these homogenous catalysts by heterogeneous solid catalysts. In fact, solid acids are advantageous as they can be easily recovered from the reaction mixture by simple filtration and can be reused after activation, thereby making the process economically viable. In continuation of our recent work on the use of solid acid catalysts [5], we now wish to introduce zeolites as effective catalysts for the acetylation of aromatic compounds under mild reaction conditions